Process of making multiply waterproof sheets



Feb. 8,1927.

L. KIRSCHBRAUN Filed Nov. 27, 1922 (QDl PROCESS 0F MAKING MULTIPLY WATERPROOF SHEETS Illini llIl l Illl:

WWW/MQ mmm Patented Feb. 8, 1927.

UNITED STATES LESTER KIRSCHBRAUN, OF CHICAGO, ILLINOIS.

PROCESS OE MAKING MULTIPLY WATERPROOF SHEETS.

Application led November 27, 1922A Serial No. 603,436.

The present invention is directed more particularly to the application of a waterproof coating interposed between a plurality of fibrous plies simultaneously with the formation of the plies.

In the present invention it is desirable that the coating' be so applied that it will fiowy on to the then upper surface of the particular ply to which it is being applied. One advantage that may result from the particular manner of applying the pitchy or bituminous film is that it materially lessens the chance of disturbing the then relatively weak wet fibrous ply which is being carried in the blanket of the paper machine. In order to more clearly understand the present invention, I have shown the accompanying drawings in which Fig. 1 is a more or less diagrammatic view of a paper machine arranged to carry out the present invention and Fig. Q is a cross-sectional view on an enlarged scale of the finished sheet.

Referring to the drawings, more particularly Fig. 2, 1, 2, 3 and Il designate the fibrous plies and between the plies 2 and 3 is interposed the bituminous or pitchy coating 5.

Referring now more particularly to Fig. 1, 6, 7 8 and 9 designate the vats, each of which is provided with cylinder molds 10 and couch rolls 11. Adjacent to the upper end of the vat 7 is mounted a distributing tank 12 adapted to hold the waterproof coating and provided with a pickup or distributing roll 13, transfer roll 14, and suction roll 15. The arrangement is such that the roll 13 picks up the coating and transfers it to the roll 14 which roll 11i applies the coating upon the upper exposed face of the fibrous ply which is being carried on the blanket 16,

The suction roll 15 tends to pull out excess of water from the coating and facilitates the even distribution of the coating over the upper face of the fibrous ply. In other r words, the fibrous ply acts as a .sort of filter and the bituminous or pitchy part of the coating in 4discrete form is distributed over the face of the ply in a relatively dry condition. By regulating the suction roll and the distributing roll, the amount of coating which is deposited on the upper face of the CFI ply may be regulated to produce a film of predetermined and variable thickness.

As the first two plies with the coating applied to the upper face of the upper ply pass between the squeeze rolls 17 and 18 they meet the two plies from the vats 8 and 9 and the four plies are thus pressed together to form a unitary structure. It will be noted that the blanket 19 acts as the top felt of the 60 paper machine going through the presses and functioning in the usual way.

It will be further noted that the cylinder molds in the vats 6 and 7 turn in the direction of the arrow while the molds in the vat-s 8 and 9 turn in the opposite direction as shown by the arrows.

The waterproof coating which is applied may take the form of an emulsion miscible in water and consisting essentially of pitch or bitumen, colloidal clay and water. This emulsion, if desired, may be formed in the manner set forth in my prior Patent No. 1,417,835.

In the drawing I have shown rolls for applying or distributing the waterproof coating onto a fibrous sheet; instead of rolls the coating might be applied by means of using suit-able spraying mechanism whereby the coating in desired quantity could be sprayed on the then Lipper surface of the particular ply in question.

I claim as my invention:

1. A method of making a waterproofed sheet, comprising separately forming a plurality of fibrous plies on forming elements of a. paper machine and subsequently to leaving the forming element causing the sheet to contact a rotating element for applying a waterproofing coating in the form of an 9( emulsion miscible in water to the upper surface Yof one of said wet plies, then pressing all of said plies together to form a unitary sheet7 and removing the water.

2. A method of making a waterproofed sheet, comprising separately forming a plui'ality of fibrous plies on cylinders of a paper machine, and subsequent to leaving the cyliuders bringing a rotating surface into contact with the upper wet surface of one of said m0 plies whereby a film of waterproofing material miscible in water is applied thereto,

then pressing all of saicl plies together to forni a unitary sheet, and removing the Water.

3. A method of makinga Waterproofed sheet, eoinprisil'ig` Separately forming a pluralityof fibrous plies on ya-paper machine, and subsequent to leaving the Sheet forming elements applying,- a film of Waterproofing material in the form of discrete particles to the upper surface o one of said plies by bringing Said surface into Contact with the Surface of an element rotating in a bulli supply of said Waterproofing material, then y pressing Aall of said plies togethery to form a unitary sheet7 and removing the Wacer.

LESTER KIRSGHBRAUN. 

